\begin{tikzpicture}
    \tkzDefPoints{0/0/O}
    \tkzDefPoint(55:1.5){A}
    \tkzDefPoint(235:1.5){B}
    \tkzDefPoint(330:1.5){C}

    \tkzDrawCircle[thick](O,A)
    \tkzDrawSegments(O,A  O,B  O,C  A,C)
    \tkzLabelPoints[above left](O)
    \tkzLabelPoints[above right](A)
    \tkzLabelPoints[right](C)
    \tkzLabelPoints[below left](B)
\end{tikzpicture}

